Group IV semiconductors (e.g., Si and Ge) are ideal materials for next-generation optoelectronic applications because they enable monolithic integration for mass production, automated full-freedom design through established design rules, and compatibility with other Group IV materials (e.g., diamond with nitrogen vacancies, carbon nanotubes with solitary dopants) for quantum emitters. Despite several decades-long efforts aimed at developing Si/Ge-based integrated optoelectronic systems, however, these applications have not yet been realized, primarily due to the absence of highly efficient Si- and Ge-based light emitters. The main roadblock to the production of Si/Ge-based light emitters is the indirect band gap of Group IV semiconductor materials, which results in high non-radiative recombination. Several efforts have focused on addressing this issue, including strain engineering, nano-structuring, and alloying. Nevertheless, a reliable, controllable, and production-compatible process for preparing direct band gap Si and Ge has yet to be achieved.